Europa vs. Titan: Which will NASA explore in its next flagship mission?

“There is an ocean beneath the icy crust of Jupiter’s moon Europa [pictured at right]. Strange creatures could be swimming in these alien waters, but so far no missions have been sent there to investigate this possibility.”

So begins, "Hoping for Europa," an article by Astrobiology magazine Editor Leslie Mullen. Squids from outer space — who could resist?

Or will it be a balloon ride over the windblown surface of a hydrocarbon lake on Titan [pictured at lower left]?

“Thick clouds extend over the entire horizon, threatening rain. The meager light that filters through illuminates one side of the balloon, making it look like a giant question mark in the sky.”

Later this week, NASA is expected to announce which moon of the outer solar system will be the target of a future $2 billion-plus “flagship mission.” It would likely be carried out as a partnership with the European Space Agency, along the lines of the Cassini-Huygens mission to Saturn.

The prospect of studying an alien ocean beckons. So does getting a closer look at Titan’s geologically active surface. The consensus seems to be that we are much more likely to find alien life on Europa than in the methane/ethane lakes of Titan. But who knows?

Either way, be patient. These missions would not launch before 2020 or so. If Titan gets the nod, expect a travel time of 9 years.

As soon as NASA decides, we’ll get back to you with some expert commentary.